1. Field of the Invention
The present invention relates to a method for producing man-made snow and an apparatus therefor, and more particularly to a method for producing man-made snow in an indoor skiing facility and an apparatus therefor.
2. Description of the Prior Arts
In recent years, indoor skiing facilities have been constructed everywhere for men and women enjoying winter sports on the outerskirts of towns and cities. It is necessary to produce snow artificially indoors and to have the snow lie on the floor at a predetermined thickness in an indoor skiing facility.
The following methods are known as such methods for producing snow:
(A) A method for producing snow by scattering a highly-water-absorbing resin (water-absorbing polymer) on brine pipes laid on the floor and having the resin disposed thereon and by freezing the resin by means of said brine pipes.
(B) A method for producing snow by making lumps of ice, then breaking the lumps of ice into small pieces, scattering the small pieces of ice on the floor and having the small pieces of ice disposed thereon.
(C) A method for producing snow by use of natural cold air with the use of a gun type snow-making machine having two-fluid nozzles jetting water together with compressed air from nozzles or with the use of a fan type snow-making machine, on a position close to a fan of which a number of water-jetting nozzles are mounted.
(D) A method for producing snow by jetting water together with compressed air into an indoor space by use of two-fluid nozzles, generating a water mist, having the mist attached to a grating mounted on a ceiling by cold air, scraping off snow/ice, to which the mist converts into and which had attached to the grating, having the snow ice fall on the floor and having the snow ice lie on the floor.
There, however, are the following problems in the above-mentioned prior art methods for producing snow:
(a) Since said method (A) is a method for making snow by freezing a polymer having absorbed water by means of brine pipes, the produced man-made snow is liable to be ice in the state of sherbet. Accordingly, it is impossible to produce compact snow and powdery snow like natural snow by the use of said method. Further, it is difficult to glide over the snow produced by the use of polymers, because of the properties of the water-absorbing polymer. When the snow produced by the use of polymers melts, the snow converts into sticky material in the state of a gel and is hard to dry when it sticks to clothes. Moreover, such snow is liable to corrode a metallic portion of skis and other metals.
(b) In said method (B), since small pieces of ice obtained by breaking lumps of ice are scattered on the floor, produced man-made snow has a form of granulated sugar. Accordingly, it is impossible to produce compact snow and powdery snow like natural snow by the use of said method. In addition, since three steps of a manufacturing of ice, a breaking of ice and a scattering of ice are required, the cost of equipment and the running cost increase.
(c) Even though said method (C) is appropriate for producing snow to be used for an outdoor skiing facility, a great amount of water and compressed air to be used are required and the calories required for converting water to ice per unit increases. Accordingly, there is a high cost of equipment for a refrigeration machine and an increased running cost. Further, since sizes of waterdrops obtained by spraying water with use of a gun type snow-making apparatus are from over 200 to 400 .mu.m, heat exchange of the waterdrops with surrounding cold air is poor. In consequence, the waterdrops are difficult to convert to snow indoors.
(d) Since snow ice attached to the ceiling is scraped off and made to fall on the floor by the use of said method (D), equipment for scraping off the snow/ice from the ceiling is required. Therefore, the cost of equipment and the running cost increase. Further, since the snow/ice is required to be wet to some extent so that the snow/ice can attach to the ceiling, it is impossible to produce powdery snow and to control properties of the snow so that the snow/ice can be of powdery snow, compact snow or ice in the state of sherbet. Furthermore, indoor temperatures have to be lowered considerably to have the mist generated by jetting water and compressed air attached to the ceiling. A great amount of calories is required therefor.